<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

/*
 * File: CaptchaSecurityImages.php
 * Author: Simon Jarvis
 * Copyright: 2006 Simon Jarvis
 * Date: 03/08/06
 * Updated: 07/02/07
 * Requirements: PHP 4/5 with GD and FreeType libraries
 * Link: http://www.white-hat-web-design.co.uk/articles/php-captcha.php
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details:
 * http://www.gnu.org/licenses/gpl.html
 *
 */

class CaptchaSecurityImages {

	function generateCode($characters) {
		/* list all possible characters, similar looking characters and vowels have been removed */
		$possible = '23456789bcdfghjkmnpqrstvwxyz';
		$code = '';
		$i = 0;
		while ($i < $characters) {
			$code .= substr($possible, mt_rand(0, strlen($possible)-1), 1);
			$i++;
		}
		return $code;
	}

	function CaptchaSecurityImages($params) {
        $font = $params["font"];
        $width = (isset($params["width"]))?$params["width"]:'120';
        $height = (isset($params["height"]))?$params["height"]:'40';
        $characters = (isset($params["characters"]))?$params["characters"]:'6';

        //dirname(__FILE__).'/monofont.ttf';
        $code = $this->generateCode($characters);
        $CI =& get_instance();
        $CI->load->library('session');
        $CI->session->set_userdata('security_code', $code);
        /* font size will be 75% of the image height */
        $font_size = $height * 0.75;
        $image = imagecreate($width, $height) or die('Cannot initialize new GD image stream');
        /* set the colours */
        $background_color = imagecolorallocate($image, 255, 255, 255);
        $text_color = imagecolorallocate($image, 20, 40, 100);
        $noise_color = imagecolorallocate($image, 100, 120, 180);
        /* generate random dots in background */
        for( $i=0; $i<($width*$height)/3; $i++ ) {
            imagefilledellipse($image, mt_rand(0,$width), mt_rand(0,$height), 1, 1, $noise_color);
        }
        /* generate random lines in background */
        for( $i=0; $i<($width*$height)/150; $i++ ) {
            imageline($image, mt_rand(0,$width), mt_rand(0,$height), mt_rand(0,$width), mt_rand(0,$height), $noise_color);
        }
        /* create textbox and add text */
        $textbox = imagettfbbox($font_size, 0, $font, $code) or die('Error in imagettfbbox function');
        $x = ($width - $textbox[4])/2;
        $y = ($height - $textbox[5])/2;
        imagettftext($image, $font_size, 0, $x, $y, $text_color, $font , $code) or die('Error in imagettftext function');
        /* output captcha image to browser */
		header('Content-Type: image/jpeg');
        imagejpeg($image);
        imagedestroy($image);
	}

}

?>